U.S. Pat. No. 4,555,546, granted Nov. 26, 1985 to Patel, discloses compatabilized polymer blends of olefin polymer, cross-linkable acrylic ester copolymer rubber, and a compatabilizing graft copolymer. The graft copolymer will contain one segment that is compatible with the olefin polymer in the above-mentioned blend; the graft copolymer will contain another segment that is compatible with the rubber in the above-mentioned blend; and these two segments are chemically linked to each other, for example, by grafting or formation of a block copolymer. The first segment is generically disclosed as including various polyolefins which optionally may also include any one of many different functional groups. Included within this description are copolymers of ethylene and an unsaturated carboxylic acid. The second segment is generically disclosed as including at least nine different classes of polymers. One of the classes so mentioned is polyaides. And finally, it is disclosed that the grafting of these segments to each other can be achieved by including in either or both of the above-described segments graft forming functional groups, or by reacting these two segments with a bi- or multi-functional compound (grafting agent). A large number of suitable functional groups and grafting agents are disclosed, among them epoxide groups and compounds containing the same. Thus, if one picks and chooses among the various possibilities generically disclosed by Patel, one can select at least some of the ingredients which are used to make the compositions of the present invention. However, nothing in Patel suggests the particular selection of ingredients which are used to make the compositions of the present invention, much less the particular quantitative limits specified for such ingredients in the compositions of the present invention, or that the compositions of the present invention are multi-phase blends which blends have at least one continuous phase that is a thermoplastic material having reactive graft sites.
U.S. Pat. No. 4,310,638, granted Jan. 12, 1982 to Coran et al., discloses thermoplastic elastomeric compositions comprising neutralized acrylic copolymer rubber modified with nylon. Coran discloses a simple two-component blend where one component comprises 60-98% neutralized acrylic rubber and the other component comprises 2-40% nylon. Coran does not recognize the significance of a third component which grafts the other two components together, nor does Coran recognize the importance of having the thermoplastic component as a continuous phase.
U.S. Pat. No. 4,338,413, granted July 6, 1982 to Coran et al., describes a complex five-component composition consisting of a blend of plastics and cured rubbers in which the plastics are a crystalline polyolefin polymer and nylon, and the rubbers are a cured particulate hydrocarbon rubber and a cured particulate polar rubber. The thermoplastic components are in turn tied together by a functionalized olefin polymer. The functionalized olefin polymer is used to improve the compatability between the crystalline polyolefin component and the nylon component. The Coran compositions require two plastics with two cured rubbers.
U.S. Pat. No. 4,602,058, granted July 22, 1986 to Graham et al., discloses blends of nylon with acid copolymers. The "thermostability and compatability" of these blends is improved by the addition of monomeric diacids. These diacids work because they inhibit interactive cross-linking between the nylon and the acid copolymer. This is the converse of the current invention, where grafting of the ethylene copolymer containing the acid moiety is not inhibited but encouraged by use of the polymeric grafting agent that links, for example, the polyamide thermoplastic and ethylene copolymer components.
U.S. Pat. Nos. 4,174,358 and 4,172,859 granted Nov. 13, 1979, and Oct. 30, 1979, respectively, to Epstein, disclose blends of thermoplastic nylon and polyester compositions containing various toughening agents, including ethylene/acrylate/methacrylic acid terpolymers and ethylene/acrylate/glycidyl methacrylate terpolymers. Three-component blends are possible, but the toughening agents are disclosed as being in a dispersed particle phase having a particle size ranging from 0.1-1 microns. Further, these compositions are disclosed as being 60-99 weight % polyamide or polyester, and the importance of the presence of both a grafting moiety and an ethylene copolymer containing an acid moiety is not recognized. The importance of regulating the specific quantity of the grafting moiety and the ethylene copolymer is not disclosed by Epstein. Finally, there is no minimum particle size required by the current invention, and often the particle size is several microns without any adverse affects on the properties of these materials.
U.S. Pat. No. 4,595,730, granted June 17, 1986 to Blondel et al., disclosed synthesis of novel polymers or oligomers which are polyamides with an ethylenic unsaturation at one end. They are made by copolymerizing amino acid monomers with a small amount of unsaturated acid which blocks one end of the nylon chain and gives the unsaturation. Alternatively, the end group can be generated from an unsaturated compound containing an epoxy group. The epoxy group then reacts with the nylon during polymerization to result in terminal unsaturation. These unsaturated polymers may be further reacted by grafting onto other polymers, including ethylene/vinyl acetate/glycidyl methacrylate terpolymers and ethylene/vinyl acetate/methacrylic acid terpolymers. However, such grafting is via the ethylenic unsaturation and not by means of an intermediate such as the epoxy group. There is no recognition of the importance of limiting the quantity of the grafting agent since no separate grafting agent is used. In addition, Blondel specifically attempts to avoid cross-linking by means of a rather cumbersome procedure, that is, specifically synthesizing nylon chains which have one and only one functional group which is available for grafting.
U.S. Pat. No. Reissue 30,754, reissued Sept. 29, 1981 on U.S. Pat. No. 3,972,961, originally granted Aug. 3, 1976 to Hammer et al., discloses graft copolymers made by reaction of nylon oligomers or other compounds which have a single reactive NH.sub.3 group on one end only. These oligomers are reacted with anhydride or equivalent groups on a trunk copolymer. The presence of only one reactive group on the nylon oligomers prevents cross-linking. The polymers obtained can be used for hot melt adhesives which have better high temperature properties than ungrafted ethylene copolymers. There is no requirement for oligomers of nylon with only one reactive group in the current invention. In fact, it is required to have high molecular weight thermoplastics, rather than oligomers, to achieve the outstanding physical properties of the current invention, and that the thermoplastics with available graft sites, have at least two or more graft sites per polymer chain.
Japanese patent No. 59-115352, published July 3, 1984, and filed by Unitika Ltd., discloses toughened polyester compositions containing 100 parts by weight of a thermoplastic polyester, 3 to 50 parts by weight of a modified polyolefin that contains an alicyclic carboxylic acid with a cis-type double bond in the ring, and 1 to 50 parts by weight of an alpha-olefin-glycidyl (meth)acrylate-vinyl acetate copolymer comprised of 80 to 99 weight % alpha-olefin, 1 to 20 weight % glycidyl (meth)acrylate, and 0 to 19 weight % vinyl acetate. Unitika discloses a clear preference for the modified polyolefin to contain vinyl acetate. In the pending application, the use of vinyl acetate is excluded. Vinyl acetate pyrolyzes at the elevated melt temperatures; e.g., those required to process the compositions of the current invention (&gt;200.degree. C. melt temperatures). One pyrolysis product, acetic acid, is detrimental to a number of the thermoplastic matrix resins described in the current invention, such as polyesters, polyamides, and polycarbonates. In addition, Unitika modified polyolefin contains alicyclic carboxylic acid (presumably dicarboxylic acid) with a cis-type double bond in the ring. The present invention avoids such acids because of inability to control the graft reaction. Finally, Unitika relates to toughening polyester compositions (compositions containing at least 50 weight % polyester). The present invention relates to flexible thermoplastic compositions which have a maximum of 50 volume % thermoplastic. At these low levels of thermoplastic, it is a key feature of the current invention that the thermoplastic be at least one of the continuous phases.
PCT publication number 85/03718 published Aug. 29, 1985 discloses toughened thermoplastic polyester compositions containing 60-97 weight % of polyester and 3-40 weight % of a toughener derived from E/X/Y where E is a radical formed from ethylene, X is a radical formed from an alkyl acrylate, and Y is glycidyl methacrylate or glycidyl acrylate. Again, these compositions are toughened polyester thermoplastics with greater than 60 weight % of polyester. These compositions have only two different polymeric components compared to the three different polymeric components required in the pending application.
U.S. Pat. No. 4,694,042 granted Sept. 15, 1987 to McKee et al, discloses thermoplastic molding materials containing 5-50 parts by volume thermoplastic material as a coherent phase and 95-50 parts by volume of crosslinked emulsion polymerized elastomeric polymers. No mention is made of grafting agent.
U.S. Pat. No. 4,404,325 granted Sept. 13, 1983 to Mason et al, discloses blends of 46-94 weight % polyamide, 5-44 weight % ionomer, and 1-12 weight % of ethylene/ester copolymer. The ethylene/ester copolymer does not contain epoxides, isocyanate, aziridine, silanes such as alkoxy or alkyl silanes, alkylating agents such as alkyl halides or alpha-halo ketones or aldehydes or oxazoline reactive groups, and therefore, Mason's ethylene/ester copolymer does not graft to the polyamide or the acid-containing ethylene copolymer as in the present invention.
U.S. Pat. No. 4,346,194 granted Aug. 24, 1982 to Roura discloses binary blends of 60-97 weight % polyamide and 3-40 weight % of a polymeric toughening agent which can be either an elastomeric olefinic copolymer having carboxyl(ate) functionality or an ionic copolymer.
PCT Publication No. WO 86/06397 published Nov. 6, 1986 discloses compositions comprising 50-95 weight % polyamide and 5-50 weight to ethylene polymer, where the ethylene polymer is a mixture of ethylene/alkyl(meth)acrylate copolymer (A) and ethylene/maleic anhydride/alkyl(meth)acrylate terpolymer (B), the ratio of A:B ranges from 1/3 to 3. Neither components (A) or (B) contain mono-carboxylic acid functionality or reactive groups selected from those used by applicant.
Japanese patent publication 59/91,148 published May 25, 1984 (abstract cited in Chemical Abstracts #193080m Vol. 101, 1984) discloses a three-component blend of polyamide 100 parts, neutralized ethylene-alpha,beta-unsaturated carboxylic acid copolymer 2-100 parts, and an ethylene-alpha-olefin copolymer 30-100 parts wherein the latter copolymer is modified with dicarboxylic acid or anhydride. As such, this latter component will not react with the acid-containing ethylene copolymer of the present invention.